Fill level measurement device with removable and replaceable components

ABSTRACT

The object of the invention is to specify a fill level measurement device, in which a measurement sensor (MS) is connected to a measurement data converter (MW), which is connected to an electrical analytical device (EA), in such a way as to simplify and abbreviate maintenance and repair work. For this purpose, the measurement data converter (MW) contains a first non-volatile memory (S 1 ), and the electronic analytical device (EA) contains a second non-volatile memory (S 2 ). The same parameter data, which are necessary to start and operate the fill level measurement device, are redundantly stored in both memories (S 1,  S 2 ). When the measurement data converter (MW) is replaced, the data stored in the second memory (S 2 ) of the electronic analytical device (EA) are automatically read into the first memory (S 1 ) of the newly installed measurement data converter (MW). When the electronic measurement data device (AE) [sic] is replaced, the data stored in the first memory (S 1 ) of the measurement data converter (MW) are automatically read into the second memory (S 2 ) of the newly installed electronic analytical device (EA). Maintenance or repair can thus be done while the system is running and no longer requires any new adjustment.

[0001] The invention relates to a fill level measurement device and a method for operating such a fill level measurement device.

[0002] To measure the fill level of solid bulk goods or of liquids in a container, several measurement principles are known. As examples, reference is made to fill level measurements by radar, vibrating rods, pressure, and capacitance measurements.

[0003] All the well-known methods have a measurement sensor connected to a converter. This common connection on the converter and sensor is called the process connection. The supply lines and the electric measurement lines of the measurement sensor are here connected to those of the converter.

[0004] Voltage flashovers can occur at the measurement sensor, which destroy parts of the measurement sensor or the electronic analytical device. For applications in hazardous areas, precautions are prescribed, such as e.g. minimum distances between the electric lines, to assure reliable protection against explosions.

[0005] The data generated by the measurement sensor are conducted to a measurement data converter which e.g. converts them into digital data, and transmits them to an electronic analytical device. Before the fill level measurement device is started, customer-specific parameter data must be entered into the fill level measurement device. When the measurement data converter or the electronic analytical device are replaced, these parameter data must be entered anew into the fill level measurement device, which results in undesirable complication.

[0006] It is the object of the invention to design a method for operating a fill level measurement device, and a fill level measurement device itself, as customer-friendly and maintenance-friendly as possible.

[0007] The invention achieves this object as regards the method by means of the process steps specified in claim 1, in that the measurement data converter contains a first non-volatile memory, and the electronic analytical device contains a second non-volatile memory, and that the same parameter data are redundantly stored in both memories.

[0008] The invention achieves its object as regards apparatus by means of the features specified in claim 7, in that the measurement data converter contains a first non-volatile memory and the electronic analytical device contains a second non-volatile memory, and that the same parameter data are redundantly stored in both memories.

[0009] The inventive fill level measuring device consists of a measurement sensor, a measurement data converter, and an electronic analytical device. The measurement sensor is situated at the measurement point, and measures the fill level, for example in a container or a tank. The measurement sensor is connected to the measurement data converter through a line. The measurement data converter generally is situated near the measurement sensor. The measurement data converter is connected to an electronic analytical device through another line. The measurement sensor transmits its measured data to the measurement data converter, which converts them into digital data, and transmits them to the electronic analytical device.

[0010] The invention specifies that the measurement data converter contains a first nonvolatile memory and the electronic analytical device contains a second non-volatile memory. The same parameter data, which are absolutely necessary to operate the fill level measurement device, are redundantly stored in both of these memories.

[0011] For example, if the measurement data converter is replaced because of a defect or for maintenance purposes, the parameter data, which are redundantly stored in the memory of the electronic analytical device, are automatically read into the memory of the new measurement data converter as soon as this has been installed. Likewise, when the electronic analytical device is replaced, e.g. because of a defect or for maintenance purposes, the parameter data, which are redundantly stored in the memory of the measurement data converter, are automatically read into the memory of the newly installed analytical device. Whether the measurement data converter or the electronic analytical device is replaced, the previously redundantly stored parameter data are again available in both memories as soon as the new device has been installed.

[0012] Because the parameter data that are necessary for starting and operating the inventive fill level measurement device are stored redundantly both in the measurement data converter and in the electronic analytical device, they no longer need to be entered anew when one of these two devices is replaced. Maintenance and repair of the inventive fill level measuring device is thus considerably abbreviated and also rendered less expensive.

[0013] The invention will now be explained in more detail in terms of the embodiment of an inventive fill level measurement device shown in the figure.

[0014] The fill level measurement device shown in the figure has a measurement sensor MS, which is connected to the measurement data converter MW by a measurement line ML. The measurement data converter MW contains a microprocessor MP1 and a non-volatile memory S1. The measurement data converter MW is connected to the electronic analytical device EA by a line LL. The electronic analytical device EA, just like the measurement data converter MW, contains a microprocessor MP2 and a nonvolatile memory S2. The microprocessor MP1 is connected to the non-volatile memory L1, while t he microprocessor MP2 is connected to the non-volatile memory S2. The two microprocessors MP1 and MP2 are connected to one another by the line LL.

[0015] When the inventive fill level measurement device is installed and first operated, the customer-specific parameter data are entered at least into one of the two non-volatile memories. They are then automatically read into the other non-volatile memory. However, they can also be read simultaneously into both non-volatile memories.

[0016] As already mentioned, when the measurement data converter MW is replaced, the data stored in the non-volatile memory S2 of the electronic analytical device EA are automatically read, via the line LL, into the non-volatile memory S1 of the just newly installed measurement data converter MW. Analogously, when the electronic analytical device EA is replaced, the data stored in the non-volatile memory S1 of the measurement data converter MW are automatically read, via the line LL, into the nonvolatile memory S2 of the just newly installed electronic analytical device EA.

[0017] Data transmission between the measurement data converter MW and the electronic analytical device EA can be e.g. asynchronous serial.

[0018] It is especially advantageous for the measurement data converter MW and the electronic analytical device EA to be electrically isolated. An especially suitable transmission medium between the measurement data converter MW and the electronic analytical device EA is e.g. an optical fiber LL or an electric conductor, with an optocoupler OK at each end. Besides the data transmission, the transmission of the supply voltage is also electrically decoupled.

[0019] The electrical isolation achieves a number of advantages, which will briefly be explained below.

[0020] The supply lines are better protected against flashovers to ground, since no voltage flashover from the process connection to the measurement sensor can occur any more, because the electronics of the measurement sensor are directly connected to ground.

[0021] Ceramic capacitive measurement sensors are used preferably for measuring the fill level, because they are distinguished by a number of indisputable advantages. However, ceramic capacitive measurement sensors have parasitic stray capacitances, between the housing and both the measurement capacitance and the reference capacitance. Due to the unavoidable coupling of interference on the lines, especially in the low frequency range, this stray capacitance can cause a relative measurement error up to 50%. The electrical isolation advantageously eliminates this measurement error completely.

[0022] In hazardous areas, minimum distances are prescribed between the process connection and the supply lines, which carry supply currents between 4 and 20 mA. However, due to the electrical isolation, the measurement sensor can very simply be built into a metallic process connection. A measurement sensor with a membrane electrode can be built in especially easily, because, due to the electrical decoupling, the membrane electrode can be electrically connected to the metallic process connection. No additional measures need to be taken any longer for protecting against explosion, such as e.g. safety distances between the process connection and the measurement data converter.

[0023] Finally, due to the electrical isolation, the measurement result is no longer garbled by the mutual coupling between the measurement data converter and the electronic analytical device. The electrical isolation thus substantially improves the signal-to-noise ratio.

[0024] As already mentioned, the electrical isolation can be realized by means of an optical fiber and two optocouplers, or e.g. by means of a transformer.

[0025] A first essential advantage of the invention is that the measurement data converter and the electronic analytical device can be replaced while the system is running. A second essential advantage is that, after replacement of the part, no new adjustment is required, because the required data are stored redundantly and are automatically read into the empty memory of the newly installed part. The invention thus substantially reduces the expenditure of time and thus also the costs for maintenance and repair.

List of Reference Symbols

[0026] EA Electronic analytical device

[0027] ML Measurement line

[0028] MP1 Microprocessor

[0029] MP2 Microprocessor

[0030] MS Measurement sensor

[0031] MW Measurement data converter

[0032] LL Optical fiber 

1. A method for operating a fill level measurement device, in which a measurement sensor (MS) is connected to a measurement data converter (MW), which is connected to an electronic analytical device (EA), such that the measurement data converter (MW) converts the measurement data received from the measurement sensor (MS) into digital data, and transmits them to the electronic analytical device (EA), characterized in that the measurement data converter (MW) contains a first non-volatile memory (S1), and the electronic analytical device (EA) contains a second non-volatile memory (S2), and that the same parameter data are redundantly stored in both memories (S1, S2).
 2. The method of claim 1, characterized in that, when the measurement data converter (MW) is replaced, the data stored in the second non-volatile memory (S2) of the electronic analytical device (EA) are automatically read into the first non-volatile memory (S1) of the newly installed measurement data converter (MW).
 3. The method of one of the claims 1 or 2, characterized in that, when the electronic analytical device (EA) is replaced, the data stored in the first non-volatile memory (S1) of the measurement data converter (MW) are automatically read into the second non-volatile memory (S2) of the newly installed electronic analytical device (EA).
 4. The method of claim 1, 2, or 3, characterized in that the data transmission between the measurement data converter (MW) and the electronic analytical device (EA) is asynchronous serial.
 5. The method of claim 1, 2, 3, or 4, characterized in that the measurement data converter (MW) and the electronic analytical device (EA) are electrically isolated.
 6. The method of claim 5, characterized in that the data and/or the supply voltage are transmitted between the measurement data converter (MW) and the electronic analytical device (EA) via an optical fiber (LL), with an optocoupler (OK) at each end.
 7. The method of claim 5, characterized in that the data and/or the supply voltage is/are transmitted between the measurement data converter (MW) and the electronic analytical device (EA) by means of a transformer.
 8. A fill level measurement device, in which a measurement sensor (MS) is connected to a measurement data converter (MW), which is connected to an electronic analytical device (EA), characterized in that the measurement data converter (MW) contains a first non-volatile memory (S1), and the electronic analytical device (EA) contains a second non-volatile memory (S2), and that the same calibration data are redundantly stored in both memories (S1, S2).
 9. The fill level measurement device of claim 8, characterized in that, when the measurement data converter (MW) is replaced, the data stored in the second non-volatile memory (S2) of the electronic analytical device (EA) are transmitted to the first non-volatile memory (S1) of the newly installed measurement data converter (MW).
 10. The fill level measurement device of claim 8 or 9, characterized in that, when the electronic analytical device (EA) is replaced, the data stored in the first non-volatile memory (S1) of the measurement data converter (MW) are transmitted to the second non-volatile memory (S2) of the newly installed electronic analytical device (EA).
 11. The fill level measurement device of claim 8, 9, or 10, characterized in that the measurement data converter (MW) and the electronic analytical device (EA) are electrically isolated.
 12. The fill level measurement device of claim 11, characterized in that the measurement data converter (MW) is connected to the electronic analytical device (EA) by an optical fiber (LL), with an optocoupler (OK) at each end.
 13. The fill level measurement device of claim 11, characterized in that the measurement data converter (MW) is connected to the electronic analytical device (EA) through a transformer. 